And I moved on to step#3; and that didn't work.
And I rebooted.And got the above error.

Rebooting helps to fix windows or to boot into a new kernel (but that's not really needed either: kexec). In Linux/Debian/aptosid a reboot will fix nothing - in reality it is the worst thing you can do is reboot if something hasn't worked. Beside that you haven't told us what hasn't worked…

Anyway: Scroll a bit down on the manual page, it tells you how to recover from a broken grub2.

_________________MfG. DonKult
"I never make stupid mistakes. Only very, very clever ones." ~ The Doctor

It pains me to confess such stupidity. But. I had three hdds in my machine, and I was mistakenly trying to fix grub on the wrong hdd.
I know now I had only to look at fstab. But I didn't know at time I was trying to work the fix.

I've decided (possibly wrongly again) that I may have created further complications doing that.And I've chosen to do a fresh install on a new hdd.

I thank you very much for your generosity in trying to help.

I'm now going to ask in another thread for some clarification to the "Moving Home" guide in the manual.